JP4067798B2 - EGR piping structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a piping structure of an EGR (exhaust gas recirculation) device that recirculates a part of exhaust gas to an intake system in order to reduce emissions and improve fuel efficiency of an internal combustion engine.
[0002]
[Prior art]
An EGR pipe that connects an exhaust manifold and an intake manifold generally passes outside the internal combustion engine, and an EGR device configured to recirculate exhaust gas to an intake system through an EGR valve and a cooling means is disclosed in Japanese Patent Application Laid-Open No. 2001-200762. There are examples described.
[0003]
In this example, the EGR pipe extending from the exhaust manifold goes around the front of the engine body (the front where the engine of the in-line cylinder is mounted vertically) and flows through the cooling water of a thermostat provided protruding from the front of the engine body. A gas path formed in the case is connected to an EGR valve attached to the upstream side of the intake pipe, and the EGR valve is connected to the intake pipe.
[0004]
[Problems to be solved by the invention]
Since the cooling part of the EGR pipe protrudes in front of the engine main body, a corresponding space is required, and the entire engine becomes large.
Since the cooling water of the thermostat is used, the temperature of the exhaust gas flowing through the gas path may affect the operation of the thermostat.
[0005]
The present invention has been made in view of such a point, and an object thereof is to arrange an EGR cooler using a space below the intake manifold to make the entire internal combustion engine compact, and to exhaust the EGR from the intake manifold. The point is to provide an EGR piping structure that can avoid the influence of the heat of the gas.
[0006]
[Means for solving the problems and effects]
In order to achieve the above object, according to the first aspect of the present invention, there is provided an EGR device that recirculates exhaust gas in an internal combustion engine to an intake system through an EGR valve and an EGR cooler. The EGR cooler is disposed in a space surrounded by the main body of the internal combustion engine, is disposed in a horizontal direction along the side surface of the cylinder block, and the inlet side connecting end of the EGR cooler is positioned on the EGR valve side. Then, the outlet side connecting end of the EGR cooler, which is connected to the EGR valve and located on the opposite side of the EGR valve, is bent and connected to the connecting end of the EGR pipe, and the EGR pipe is connected to the connecting end. The EGR pipe structure was further bent and extended obliquely upward in parallel to the EGR cooler and connected to the intake manifold .
[0007]
Since the EGR cooler is disposed using a dead space surrounded by the intake manifold, the intake manifold stay, and the internal combustion engine body, the entire internal combustion engine can be made compact by effectively utilizing the space.
The EGR cooler can avoid the influence of EGR exhaust gas heat on the intake manifold as much as possible. [0008]
According to a second aspect of the present invention, in the EGR piping structure according to the first aspect, only the EGR cooler is disposed below the intake manifold.
[0009]
Therefore, only the EGR cooler having a relatively low temperature in the EGR pipe is close to the intake manifold, and the heat of the exhaust gas of the EGR does not affect the intake manifold and does not increase the intake air temperature. Can be maintained.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
A schematic diagram of the piping structure of the EGR apparatus according to the present embodiment is shown in FIG.
The cylinder head 2 of the internal combustion engine 1 has an exhaust manifold 3 on one side wall and an intake manifold 4 on the opposite side wall.
[0011]
An EGR internal passage 5 communicating with the exhaust manifold 3 is formed in the cylinder head 2, an EGR valve 7 is provided at the outlet of the EGR internal passage 5 via an EGR passage 6, and an EGR pipe 8 extending from the EGR valve 7. Are coupled to the EGR cooler 10, and an EGR pipe 9 extending from the EGR cooler 10 is coupled to the intake manifold 4.
[0012]
Therefore, a part of the exhaust gas (EGR gas) discharged to the exhaust manifold 3 of the internal combustion engine 1 is guided to the EGR passage 6 through the EGR internal passage 5 in the cylinder head 2 and introduced into the EGR valve 7, and EGR The EGR cooler 10 cools the valve 7 through the EGR pipe 8 and returns to the intake manifold 4 from the EGR pipe 9.
[0013]
The internal combustion engine 1 according to the present embodiment is an in-line four-cylinder internal combustion engine, the whole of which is shown in a perspective view in FIG. FIG. 3 is a perspective view, and FIG. 4 is a perspective view of a main part viewed from the intake manifold 4 side.
[0014]
As shown in FIG. 3, the exhaust manifold 3 is attached to one side of the cylinder head 2 so as to be parallel to the cylinder arrangement direction, and the end of the exhaust manifold 3 is integrally formed as an EGR pipe 3a.
This EGR pipe 3 a communicates with an EGR internal passage 5 formed at the end of the cylinder head 2.
[0015]
On the other hand, a long intake manifold 4 is attached to the opposite side surface of the cylinder head 2 in the cylinder arrangement direction, and an end of one end of the intake manifold 4 is supported by an intake manifold stay 12 interposed between the cylinder block 11. Yes.
[0016]
The intake manifold stay 12 has an upper end fixed to the tip of one end of the intake manifold 4 and a lower end screwed to the cylinder block 11 with bolts 13 to support the intake manifold 4.
[0017]
On the other hand, as shown in FIG. 5, the fuel pump 20 is attached to the center of the end surface of the cylinder head 2 on the side where the EGR internal passage 5 is formed, and the cam sensor 21 is attached to the upper part adjacent to the fuel pump 20.
[0018]
An outlet 5a of an EGR internal passage 5 formed in the cylinder head 2 is opened as shown in FIG. 5 below the cam sensor 21 on the intake manifold 4 side of the fuel pump 20 on the same end face of the cylinder head 2; The EGR passage 6 is fixed to the outlet portion, and the EGR valve 7 is attached through the EGR passage 6.
[0019]
The EGR passage 6 has a connecting portion connecting the upstream side wall 6a on the cylinder head 2 side and the downstream side wall 6c on the EGR valve 7 side, and the opening of the downstream side wall 6c with respect to the opening of the upstream side wall 6a. However, the passage of the connecting portion is formed obliquely so as to shift in the opposite direction to avoid the fuel pump 20.
[0020]
Mounting holes 6d are formed in the three corners of the upstream side wall 6a of the EGR passage 6, and three bolt holes 2a surrounding the outlet 5a on the cylinder head 2 side correspond to the three mounting holes 6d. The bolt 14 passes through the mounting hole 6d of the EGR passage 6 and is screwed into the bolt hole 2a of the cylinder head 2 so that the EGR passage 6 is attached to the cylinder head 2.
[0021]
Two bolt shafts 15 project from left and right corners sandwiching the opening of the downstream side wall 6c of the EGR passage 6, and bolt holes 6e are formed at the other corner, and the EGR valve 7 has left and right sides of the body case. Two mounting holes 7a corresponding to the two bolt shafts 15 and mounting holes 7b corresponding to the bolt holes 6e are formed, and the two bolt shafts 15 pass through the EGR valve 7 through the two mounting holes 7a. The nut 16 is screwed into the threaded end of the bolt shaft 15 projecting through the bolt shaft 15, the bolt 17 is passed through the mounting hole 7 b and screwed into the bolt hole 6 e to tighten the EGR valve 7. Secure to the passage 6.
[0022]
Thus, the EGR valve 7 attached to one side surface of the cylinder head 2 via the EGR passage 6 extends an EGR pipe 8 from the lower end portion thereof.
The EGR pipe 8 extending downward from the EGR valve 7 is bent substantially horizontally and extends toward the lower space of the intake manifold 4.
[0023]
Below the intake manifold 4, there is a space between the cylinder block 11 and the intake manifold stay 12, and an EGR cooler 10 is disposed in this space in the horizontal direction along the side surface of the cylinder block 11 (see FIG. 4).
A connecting end 8 a of an EGR pipe 8 extending from the EGR valve 7 is coupled to the connecting end 10 a of the EGR cooler 10.
[0024]
The EGR cooler 10 is attached to the cylinder block 11 and guides engine cooling water into the case to cool the extension portion of the EGR pipe 8, thereby cooling by taking the heat of the EGR gas passing through the inside.
[0025]
The other connecting end portion 10b of the EGR cooler 10 is bent and coupled to the connecting end portion 9a of the second EGR pipe 9, and the EGR pipe 9 is further bent from the connecting end portion 9a and obliquely upward in parallel with the EGR cooler 10. The connecting end 9b is coupled to the connecting end 4a of the intake manifold 4 above the EGR cooler 10.
[0026]
Only the relatively low-temperature EGR cooler 10 is located below the intake manifold 4, and the high-temperature EGR pipes 8 and 9 extending from both ends of the intake manifold 4 are out of the space below the intake manifold 4.
In front of the intake manifold stay 12, electrical components such as a starter motor 22 are arranged, and harnesses 23 are arranged (see FIG. 2).
[0027]
Since it is configured as described above, the EGR gas that has entered the EGR internal passage 5 of the cylinder head 2 from the exhaust manifold 3 is slightly cooled by the cooling water in the water jacket in the cylinder head 2, and the intake side of the cylinder head 2 The EGR valve 7 is introduced into the EGR valve 7 through the EGR passage 6 from the outlet 5 a of the close EGR internal passage 5.
[0028]
The EGR gas controlled by the EGR valve 7 and discharged to the EGR pipe 8 is led to the EGR pipe 8 and is cooled by entering the EGR cooler 10 disposed below the intake manifold 4, and then passes through the EGR pipe 9. It is supplied to the intake manifold 4.
[0029]
A starter motor 22 and a harness 23 are disposed on the intake manifold 4 side of the internal combustion engine. An EGR cooler 10 that cools EGR gas is provided between the intake manifold stay 12 and the cylinder block 11 below the intake manifold 4. Since it is arranged using the dead space between them, the entire internal combustion engine 1 can be made compact by effectively utilizing the space.
[0030]
Of the EGR piping, only the EGR cooler 10 is close to the lower side of the intake manifold 4, and the heat of the EGR gas passing through the EGR cooler 10 while being covered with the cooling water is shielded by the cooling water, so that the EGR cooler 10 itself. Since the intake manifold 4 is not affected by heat at a relatively low temperature, the output of the internal combustion engine 1 can be maintained without increasing the intake air temperature.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a piping structure of an EGR device according to an embodiment of the present invention.
FIG. 2 is a perspective view showing the whole internal combustion engine according to the present embodiment with a part of auxiliary machinery arranged therein.
FIG. 3 is a partial perspective view seen from the exhaust manifold side.
FIG. 4 is a perspective view of a main part viewed from the intake manifold 4 side.
FIG. 5 is an exploded perspective view showing an EGR valve mounting structure.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Cylinder head, 3 ... Exhaust manifold, 4 ... Intake manifold, 5 ... EGR internal passage, 6 ... EGR passage, 7 ... EGR valve, 8 ... EGR pipe, 9 ... EGR pipe, 10 ... EGR cooler 11 ... Cylinder block, 12 ... Intake manifold stay, 13, 14 ... Bolt, 15 ... Bolt shaft, 16 ... Nut, 17 ... Bolt, 20 ... Fuel pump, 21 ... Cam sensor, 22 ... Starter motor, 23 ... Harness

Claims (2)

In an EGR device that recirculates exhaust gas in an internal combustion engine to an intake system via an EGR valve and an EGR cooler,
The EGR cooler is disposed in a space surrounded by an intake manifold, an intake manifold stay, and an internal combustion engine body ;
The EGR cooler is disposed in the horizontal direction along the side surface of the cylinder block,
An inlet side connecting end portion of the EGR cooler is located on the EGR valve side and connected to the EGR valve,
The outlet side connecting end of the EGR cooler located on the opposite side of the EGR valve is bent and coupled to the connecting end of the EGR pipe,
The EGR pipe structure is further bent from a connecting end portion thereof and extends obliquely upward in parallel with the EGR cooler and is connected to an intake manifold .   2. The EGR piping structure according to claim 1, wherein only the EGR cooler is disposed below the intake manifold.

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